2种导电炭黑复合橡胶体系的导热性能研究

研究了2种导电炭黑复合天然橡胶材料的导热性能随着温度和填料用量的变化规律。结果表明,温度对于导电炭黑复合体系导热性能的影响不大。乙炔黑复合体系具有极高的导热性能,随着炭黑用量的增加,其导热性能优势越加明显。据透射电镜观察填料的微观形态,乙炔黑链枝状结构丰富,聚集体之间以面接触为主,这是其复合橡胶导热性能优异的原因,乙炔黑复合材料的热导率与炭黑体积分数呈线性关系。40B2复合体系的热导率与炭黑体积分数呈现逾渗规律,逾渗阈值在炭黑体积分数8.30%至13.63%之间。据扫描电镜观察复合材料的微观结构,逾渗现象与炭黑在基体内的分布密切相关。为更精确地描述填料用量与复合体系热导率的关系,对2种复合体系的热导率与炭黑的体积分数进行了回归。     

Microwave absorbing rubber composites containing carbon black and aluminum powder

Natural rubber (NR), epoxidized natural rubber (ENR), and chlorosulfonated polyethylene (CSM) composites filled with conductive carbon black and aluminum powder have been prepared by using a two‐roll mill. An electromagnetic interference shielding effectiveness of those rubber composites was carried out in the frequency range of 8–12GHz (X‐band microwave). The increase of filler loading enhanced shielding effectiveness of the rubber composites. Conductive carbon black was more effective in shielding than aluminum powder. Binary filler‐filled rubber composites showed higher shielding effectiveness than that of single filler‐filled rubber composites. It has been observed that the shielding effectiveness of these rubber composites could be ranked in the following order: ENR ≥ CSM > NR, whereas the mechanical properties of the rubber composites were in the order of CSM > ENR > NR. The correlation between shielding effectiveness and electrical conductivity as well as mechanical properties of the rubber composites are also discussed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and Characterization of Conducting Composites of Polypyrrole/Polypyrrole-Coated Short Nylon Fiber and Natural Rubber

Pyrrole was polymerized in the presence of anhydrous ferric chloride as oxidant and p-toluene sulphonic acid as dopant. Polypyrrole-coated short Nylon fibers were prepared by polymerizing pyrrole in the presence of short Nylon fibers. The resultant polypyrrole (PPy) and polypyrrole-coated Nylon fiber (F-PPy) were characterized using SEM and then used to prepare rubber composites based on natural rubber. The cure pattern, cure kinetics, filler dispersion, DC conductivity, mechanical properties and morphology of the resulting composites were studied. The presence of PPy-coated fibers in the natural rubber/PPy system reduced the cure time significantly. The DC conductivity of the composites was found to be better for the F-PPy system compared to PPy-filled NR composite. The F-PPy system also showed better tensile strength, modulus and tear resistance.     

Effects of palm ash loading and maleated natural rubber as a coupling agent on the properties of palm‐ash‐filled natural rubber composites

Natural rubber composites were prepared by the incorporation of palm ash at different loadings into a natural rubber matrix with a laboratory‐size two‐roll mill (160 × 320 mm²) maintained at 70 ± 5°C in accordance with the method described by ASTM D 3184–89. A coupling agent, maleated natural rubber (MANR), was used to improve the mechanical properties of the natural rubber composites. The results indicated that the scorch time and cure time decreased with increasing filler loading, whereas the maximum torque exhibited an increasing trend. Increasing the palm ash loading increased the tensile modulus, but the tensile strength, fatigue life, and elongation at break decreased. The rubber–filler interactions of the composites decreased with increasing filler loading. Scanning electron microscopy of the tensile fracture surfaces of the composites and rubber–filler interaction studies showed that the presence of MANR enhanced the interfacial interaction of the palm ash filler and natural rubber matrix. The presence of MANR also enhanced the tensile properties and fatigue life of palm‐ash‐filled natural rubber composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Safe amine based zinc dithiocarbamates for the vulcanization of carbon black reinforced natural rubber

Binary combination of three safe amine based synthesized zinc dithiocarbamates (ZDC), namely zinc (N‐benzyl piperazino) dithiocarbamate (ZBPDC), zinc (N‐ethyl piperazino) dithiocarbamate (ZEPDC), and zinc (N‐phenyl piperazino) dithiocarbamate (ZPPDC) with mercapto benzothiazole disulfide (MBTS) as an effective accelerator system for the vulcanization of carbon black (N330, N550, and N774) filled natural rubber (NR) composites are studied. A comparison between the safe amine based zinc dithiocarbamates with the unsafe zinc dimethyl dithiocarbamate (ZDMC) in the light of mechanical and aging resistance behavior, introduces the non carcinogenic rubber additives in the filled vulcanization of rubber. Both accelerator and filler have the major importance for improving the mechanical as well as aging resistance behavior of the resultant vulcanizate. Variation in the filler and also filler to oil ratio are done to optimize the mechanical properties. SEM studies of different types of filler with different amounts show that N330 at 30 phr loading composites forms more homogeneity and less aggregated structures. Natural rubber systems with N330 carbon black show the best results with respect to tensile strength, but after the aging N774 carbon black filled system indicates better retention in the tensile strength. ZPPDC‐MBTS accelerated vulcanizate shows the better age resistance behavior than ZDMC‐MBTS accelerated vulcanizate. From both the points of age resistance and mechanical properties, ZBPDC‐MBTS accelerator system is the suitable substitute for ZDMC‐MBTS accelerated system in the filled vulcanization of natural rubber composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39988.     

Effect of a coupling agent on the properties of hemp‐hurd‐powder‐filled styrene–butadiene rubber

Styrene–butadiene rubber (SBR) composites filled with hemp hurd powder (HP) were prepared with bis(3‐triethoxysilylpropyl) tetrasulfide (Si69) as a coupling agent. The effects of the filler content and coupling agent on the curing characteristics and dynamic mechanical properties of the composites were studied. The results indicate that with increasing filler loading, the torque values increased and the curing time decreased. The mechanical properties improved with increasing filled HP content up to 60 phr. Usually, long fibers led to a sharp decrease in the toughness of the composites, whereas short fibers, such as HP, had a positive effect on the elongation at break within the loading range studied. The extent of the filler–matrix interaction and the scanning electron micrographs of the fractured surfaces confirmed that the addition of Si69 improved the interfacial interaction between HP and the SBR matrix, which led to an increase in the maximum torque and the mechanical properties. Moreover, the coupling agent was helpful in dispersing the filler in the rubber matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Comparative Study of the Cure Characteristics and Mechanical Properties of Natural Rubber Filled With Different Calcium Carbonate Resources

Bio‐waste materials such as eggshell (ES) and fishbone (FB) were used as new fillers compared with commercial calcium carbonate (CC) in natural rubber composite. The effect of their presence in the rubber mix on the rheometric study, morphology, mechanical properties, hardness, and abrasion resistance has been investigated at constant filler content (30 phr). The filler and their composites were characterized by Fourier‐transform infrared, X‐ray diffraction, thermogravimetric analysis, and scanning electron microscope (SEM). The results showed that the cure time and scorch time of the composites filled with CC and ES are lower than the composites filled FB filler. On the other hand, composites with ES and CC showed enhanced values of tensile, modulus at 100% and 300% elongation, hardness, and abrasion resistance. The morphological data revealed that CC and ES fillers are better dispersed in the rubber matrix than FB filler. J. VINYL ADDIT. TECHNOL., 26:309–315, 2020. © 2019 Society of Plastics Engineers     

Flow properties of natural rubber composites filled with defatted soy flour

The linear and nonlinear viscoelastic properties of natural rubber composites reinforced with defatted soy flour (DSF) were studied. DSF is an abundant, renewable commodity, and its rigid nature makes it suitable as a reinforcement phase in rubber composites. At small strain, the elastic modulus of a 30% filled composite was about 20 times higher than the unfilled rubber. Greater reinforcement was observed for carbon black filled composites than for DSF filled composites at filler concentrations of 10 and 20%. At high strain, values of the relaxation modulus dropped more rapidly for highly filled DSF composites. At high shear rates in a capillary viscometer, a small reinforcement effect remained for all composites, and lower die swell was observed for DSF composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Guayule natural rubber composites: impact of fillers on their cure characteristics,dynamic and mechanical behavior

Guayule natural rubber (GNR) is an alternative resource of Hevea natural rubber (HNR) with 99.9% cis content in its 1,4-polyisoprene chemical backbone. In this study, compounds were formulated independently with four different reinforcing fillers such as carbon black (HAF), precipitated silica (VN3), fume silica (FUM) and nanofly ash (NFA) for the advancement of GNR based products. The cure characteristic, dynamic-mechanical performance and mechanical properties of GNR composite were studied with the reinforcing effect of different fillers on GNR. The cure characteristic results demonstrated that HAF and FUM silica filled compounds had more processing safety than VN3 and NFA filled compounds. Viscoelastic parameters of the vulcanizates were studied by dynamic mechanical analysis to estimate the glass transition characteristics and dynamic behavior. The higher storage modulus of FUM silica vulcanizate was an indication of superior filler reinforcing nature and improved rolling resistance than other filled systems. Additionally, HRTEM analysis also proved the better filler dispersion ability of FUM silica in GNR matrix. The mechanical properties were studied with a variation of each filler loading of 8, 16, and 32 phr in GNR vulcanizates. The tensile strength of each filled system increased with an increase of filler content from 8 to 32 phr. In comparison, FUM silica GNR vulcanizates exhibited better mechanical properties, therefore, it was considered as a better structure-performance composite than those of HAF, VN3 and NFA filled composites.

     

Curing characteristics and mechanical properties of rattan‐powder‐filled natural rubber composites as a function of filler loading and silane coupling agent

Curing characteristics, tensile properties, morphological studies of tensile fractured surfaces using scanning electron microscopy (SEM), and the extent of rubber filler interactions of rattan‐powder‐filled natural rubber (NR) composites were investigated as a function of filler loading and silane coupling agent (CA). NR composites were prepared by the incorporation of rattan powder at filler loading range of 0–30 phr into a NR matrix with a laboratory size two roll mill. The results indicate that in the presence of silane CA, scorch time (t_s2), and cure time (t₉₀) of rattan‐powder‐filled NR composites were shorten, while, maximum torque (M_H) increased compared with NR composites without silane CA. Tensile strength and tensile modulus of composites were enhanced whereas elongation at break reduced in the presence of silane CA mainly due to increase in rubber‐filler interaction. It is proven by SEM studies that the bonding between the filler and rubber matrix has improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hybridized reinforcement of natural rubber with silane‐modified short cellulose fibers and silica

Natural‐rubber‐based hybrid composites were prepared by the mixture of short cellulose fibers and silica of different relative contents with a 20‐phr filler loading with a laboratory two‐roll mill. The processability and tensile properties of the hybrid composites were analyzed. The tensile modulus improved, but the tensile strength and elongation at break decreased with increasing cellulose fiber content. The scorch safety improved with the addition of 5‐phr cellulose fiber in the composites. The Mooney viscosity significantly decreased with increasing cellulose fiber content. To modify the surface properties of the cellulose fiber and silica fillers, a silane coupling agent [bis(triethoxysilylpropyl)tetrasulfide, or Si69] was used. The effects of Si69 treatment on the processing and tensile properties of the hybrid composites were assessed. We found that the silane treatment of both fillers had significant benefits on the processability but little benefit on the rubber reinforcement. The strength of the treated hybrid composite was comparable to that of silica‐reinforced natural rubber. Furthermore, to investigate the filler surface modification and to determine the mixing effects, infrared spectroscopic and various microscopic techniques, respectively, were used. From these results, we concluded that the fillers were better dispersed in the composites, and the compatibility of the fillers and natural rubber increased with silane treatment. In conclusion, the hybridized use of short cellulose fibers from a renewable resource and silica with Si69 presented in this article offers practical benefits for the production of rubber‐based composites having greater processability and more environmental compatibility than conventional silica‐filler‐reinforced rubber. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Oil palm wood flour filled natural rubber composites: fatigue and hysteresis behaviour

The fatigue and hysteresis behaviour of oil palm wood flour (OPWF) filled natural rubber composites was studied. The stress at any strain decreased with increasing OPWF loading in the composites. As the filler loading increased, the poor wetting of the OPWF by the rubber matrix gave rise to poor interfacial adhesion between the filler and rubber matrix. Results also indicate that the composite with the highest loading of OPWF was the most sensitive towards changes in strain energy, and hence exhibited the highest hysteresis. Thermal ageing not only reduced the fatigue life, but also increased the hysteresis of the composites. © 2000 Society of Chemical Industry     

天然橡胶湿法混炼的研究进展

根据补强填充体系种类,分别介绍炭黑、白炭黑和石墨烯等与天然橡胶的湿法混炼工艺技术,并对天然橡胶湿法混炼所面临的问题及发展趋势进行了分析和展望。湿法混炼研究包括不同补强填充体系水乳液的配制方式和配方优化及湿法混炼胶的后处理工艺。今后应对湿法混炼多组分复杂反应的特征和混炼胶结构与性能的关系开展深入研究,并加强自动化与连续化生产工艺的研发。     

Properties of natural rubber composites reinforced with silica or carbon black: influence of cure accelerator content and filler dispersion

Filler dispersion is a critical factor in determining the properties of filled rubber composites. Silica has a high density of silanol groups on the surface, which lead to strong filler–filler interactions and a poor filler dispersions. A cure accelerator, N‐tert‐butyl‐2‐benzothiazole sulfenamide (TBBS), was found to improve filler dispersion in silica‐filled natural rubber (NR) compounds. For the silica‐filled NR compounds without the silane coupling agent, the reversion ratio generally increased with increase in TBBS content, whereas those of the silica‐filled NR compounds containing the silane coupling agent and carbon black‐filled NR compounds decreased linearly. The tensile strength of the silica‐filled NR vulcanizate without the silane coupling agent increased as the TBBS content increased, whereas carbon black‐filled samples did not show a specific trend. The experimental results were explained by TBBS adsorption on the silica surface and the improvement of silica dispersion with the aid of TBBS. Copyright © 2003 Society of Chemical Industry     

Autoclaved aerated concrete waste (AACW): An alternative filler material for the natural rubber industry

Material waste from the production of autoclaved aerated concrete, a porous material, should be considered as a valuable byproduct for use as a filler material for the rubber industry. Natural rubber (NR) composites filled with different loading (over the range of 0–60 phr) of autoclaved aerated concrete waste (AACW) as a new eco‐friendly material were produced using two roll mills and then were studied for their cure characteristics, mechanical and aging properties, and morphology, and also compared with commercial fillers, calcium carbonate (CaCO₃), and silica (SiO₂). In most cases, the cure characteristics and mechanical and aging properties of the SiO₂‐filled NR composites were significantly better than those of the AACW‐ and CaCO₃‐filled NR composites. However, these properties for AACW‐filled composites appeared to be higher than CaCO₃‐filled composites. The reason for this could be due to a larger surface area which is both porous and of an irregular shape of the AACW filler used. Scanning electron microscope images showed that the morphology of the rubber filled with SiO₂ was finer and more homogenous compared with the rubber filled with AACW or CaCO₃. Overall results revealed that the reinforcement ability of AACW‐filled NR composites was generally better when compared with CaCO₃‐filled NR composites; therefore, AACW can be used effectively as a cheaper filler for production of rubber products where end‐use properties of a rubber product is specifically required. POLYM. COMPOS., 36:2030–2041, 2015. © 2014 Society of Plastics Engineer     

Effective reinforcement of hydrogen-bonding assembly silica-graphene hybrid in natural rubber

Silica-graphene hybrid (HGKS) with good dispersion and strong interfacial interactions was fabricated by hydrogenbonding assembly. HGKS was incorporated into natural rubber (NR) to develop high-performance tire treads. During vulcanized process of HGKS filled NR (NR/HGKS), HGKS can participate in the process to form dual dynamic network structure. The interfacial interaction between HGKS and NR due to the dispersion of HGKS was investigated. The strong covalent interaction between NR and HGKS is the most important factor to determine the ultimate performance of rubber composites. In this contribution, a series of HGKS with different hybrid grafting ratio are prepared to reveal the effects of changes in filler surface properties on the structure and mechanical properties of rubber composites. It has been demonstrated that it is an effective hybrid technique to drastically improve its dispersibility in NR and form strong interfacial reactions, and HGKS is expected to be used as a new type of reinforcing filler for the manufacture of high-performance green tire materials.     

Reinforcing mechanisms of carbon nanotubes and high structure carbon black in natural rubber/styrene‐butadiene rubber blend prepared by mechanical mixing − effect of bound rubber

The reinforcing effect of high structure carbon black (HSCB) and multi‐walled carbon nanotubes (MWCNTs) on natural rubber/styrene‐butadiene rubber blend processed using mechanical mixing was comparatively investigated. In‐depth analysis by dynamic mechanical analysis, the Eggers ? Schummer model and Medalia's relationship showed that HSCB aggregates provided large internal pores leading to significant immobilized macromolecules in filled rubber. Additionally, a tubular immobilized rubber layer with a thickness of 8 nm was estimated for the rubber/MWCNT system based on dynamic mechanical analysis data. The mechanical performance of the HSCB filled blend was higher than that of the MWCNT filled blend at the same loading which was correlated to its higher bound rubber content. Both bound rubber content and filler anisotropy were found to govern the overall mechanical properties of rubber/MWCNT composites. Stress softening was correlated with rupture energy suggesting hysteretic failure mechanisms in both MWCNT and HSCB filled rubbers. © 2015 Society of Chemical Industry     

Study on Tensile,Electrical, and Thermal Properties of Aluminium Particle Filled Natural Rubber (NR) and Ethylene-Propylene-Diene Terpolymer (EPDM) Composites

Comparative studies on the effect of aluminium particles in natural rubber (NR) and ethylene-propylene-diene terpolymer (EPDM) were conducted. The incorporation of aluminium particles in NR or EPDM composites increased the cure time, t ₉₀, and scorch time, t _S2 . At a fixed filler loading, EPDM composites exhibited longer t ₉₀ and t _S2 than NR composites. The results also indicate that the maximum torque, M _H of aluminium filled NR and EPDM composites increase with increasing filler loading. For tensile properties, EPDM composites show lower tensile properties than NR composites. Thermogravimetric analysis (TGA) results show that aluminium filled EPDM composites have better thermal stability than aluminium filled NR composites.

The results for electrical properties indicate that the electrical properties of aluminium filled NR and EPDM composites increase with increase in filler loading.     

Influence of carbon black in polychloroprene organoclay nanocomposite with improved mechanical,electrical and morphology characteristics

Abstract

The effect of carbon black on nanoclay filled polychloroprene (CR) composites has been investigated. The nanoclay loading is fixed at 5 part per hundred rubbers (phr), and carbon black loading varied from 5 to 20 phr in rubber compounds. The rubber nanocomposites are prepared in laboratory by mixing in two-roll mill. The addition of nanoclay enhances mechanical properties especially tear strength and decreases water absorption without change in electrical properties compared to gum rubber vulcanisates. Wide angle X-ray diffraction and transmission electron microscopy are used to study the microstructure of CR nanocomposites. The addition of 5 parts of nanoclay to 15 phr carbon black filled samples shows synergistic effect between the fillers and suggests that the reinforcement is due to a more developed filler network formation in hybrid filler system than that in single phase filler. Significant improvement in mechanical, electrical and low water absorption properties has been obtained with these nanoclay and carbon black filled rubber nanocomposites. The paper concludes that nanocomposites containing a mixture of organoclay and carbon black in right proportion can be a substitute for rubber components used in underwater cable and device encapsulation applications.     

Natural rubber protein as interfacial enhancement for bio‐based nano‐fillers

Natural rubber was enhanced with soy protein nano‐aggregates and carbon black using a hybrid process. The rubber composites reinforced with an optimum amount of soy protein or soy protein/carbon black showed useful tensile properties. The stress‐strain behaviors were analyzed with a micro‐mechanical model that describes the stress–strain measurements well. The model analysis provides insight into filler network characteristics and entanglement modulus. The composites were also analyzed with both linear and nonlinear viscoelastic properties. Temperature and frequency dependent modulus as well as the model analysis of stress softening effect describe the ability of soy protein to constraint polymer chains in the highly filled composites. For the composites reinforced with soy protein, the good tensile properties are attributed to good filler‐polymer adhesion through the compatibilization effect of natural rubber protein. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2188–2197, 2013